1. Field of the Invention
The present invention relates to a strainer for extracting debris from waste water discharged from a sink or the like, and, more particularly, to a drain strainer embody in construction in relation of parts to enable cleaning of debris between periods of prolong use of a strainer without undue restriction to the flow of water.
2. Description of the Prior Art
U.S. Pat. No. 6,153,095 discloses a filter canister added to a sink drain and includes a dissolvable sanitation table that can be removed for replacement the filter element in the canister. The supported structure for the filter element and the relative size of the element limits the drain area for wastewater. As the filter element, formed of mesh material such a fiber plastic, becomes progressively restricted by the entrapment of the debris there is likely to be a restraint to the flow space for the wastewater and may actual promote plugging causing water flow stoppage.
It is well known in the art to provide a p-trap or other plumbing facility as a site for debris removal to avoid clogging of the drain line for wastewater particularly at inaccessible sites along the course of the drain line. The p-trap or other facility sometimes fails to prevent clogging of the drain and requires the services of a plumber to mechanically remove the debris or the use of chemicals to fragment the clogging matter sufficiently to restore normal flow of the wastewater. The use of chemicals introduces a pollutant to the wastewater stream and, additionally, introduces a safety hazard to the living environment of a person. The operation of a p-trap or other facility to entrap potentially drain clogging substances may be ineffective when small articles e.g. toothpaste caps, are not retained and fail to pass an already existing restriction in a drain line. In addition, circumstances occur when it is desirable to recover articles such as rings, contact lenses, etc. inadvertently entering the drain but cannot be recovered by a conventional entrapment facilities. Lastly, it is desirable to allow a systematic removal of materials such as hair from the drain water to avoid the periodic clogging of a particular drain line used to carry hair-laden wastewater.
It is well known in the art to use a modified construction of the water trap or equivalent structure of a plumbing facility as a site for debris removal to avoid clogging of the drain line for wastewater. This requires replacement of the water trap to install the facility for allowing debris removal and thereafter systematic draining of the water trap to allow the operation of the debris removal facility. The present invention avoids the costs to replace the water trap and the inconvenience and exposure to the wastewater when desired to clean collected debris from the removal facility. Additionally, the present invention seeks to always maintain the original area in the drain line for the intended flow of wastewater by providing a flow space in a strainer is many times larger the original flow space in the drain line.
A serious operating problem occurs when a strainer is located in the area of the drain line used to form the conventional water trap. Water pressure is necessary to force sufficient water through the strainer even in the absence of debris to equalize the water level in the trap. This creation of water pressure artificially increases a column height of water at the entrance to the trap to such an extent that a leakage commonly occurs at the site of the annular seal acted on by the slip joint nut. This type of seal is not designed to perform in the presence of a positive water pressure and therefore allows leakage. The leakage condition is prolonged as, for example, when the presence of debris in the strainer extends the residence time of the column of water at the elevation of the slip joint nut.
Accordingly, it is an object of the present invention to provide a strainer with an effective collection and retention cavity for collecting debris from a drain provided with a drain line segment constructed to support the strainer for ease of cleaning by incorporating the strainer at a drain site that is readily accessible and readily serviceable.
It is another object of the present invention to provide an improved construction for a drain strainer having a debris collection sight sufficiently large and with apertures for wastewater to ensure periods of long use without the need to remove debris.
It is a further object of the present invention to provide a drain strainer, which can be removed and readily replaced in a drain line without the need of tools and constructed to preclude incorrect assembly to form a watertight structure.